Javascript 我可以使用 jQuery 检查是否至少选中了一个复选框？
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Can I use jQuery to check whether at least one checkbox is checked?
提问by Jake
I have the following HTML form which can have many checkboxes. When the submit button is clicked, I want the user to get a javascript alert to check at least one checkbox if none are checked. Is there an easy way to do this using jQuery?
我有以下 HTML 表单，其中可以有许多复选框。单击提交按钮时，如果没有选中任何复选框，我希望用户收到一个 javascript 警报以检查至少一个复选框。有没有一种简单的方法可以使用 jQuery 做到这一点？
<form name = "frmTest" id="frmTest">
<input type="checkbox" value="true" checked="true" name="chk[120]">
<input type="checkbox" value="true" checked="true" name="chk[128]">
<input type="checkbox" name="chk[130]">
<input type="checkbox" name="chk[143]">
<input type="submit" name="btnsubmit" value="Submit">
</form>
回答by Quentin
if(jQuery('#frmTest input[type=checkbox]:checked').length) { … }
回答by Matthew Flaschen
$('#frmTest input:checked').length > 0
回答by Jon
$("#frmTest").submit(function(){
var checked = $("#frmText input:checked").length > 0;
if (!checked){
alert("Please check at least one checkbox");
return false;
}
});
回答by chithon
$("#show").click(function() {
var count_checked = $("[name='chk[]']:checked").length; // count the checked rows
if(count_checked == 0)
{
alert("Please select any record to delete.");
return false;
}
if(count_checked == 1) {
alert("Record Selected:"+count_checked);
} else {
alert("Record Selected:"+count_checked);
}
});
回答by Domingo
$('#fm_submit').submit(function(e){
e.preventDefault();
var ck_box = $('input[type="checkbox"]:checked').length;
// return in firefox or chrome console
// the number of checkbox checked
console.log(ck_box);
if(ck_box > 0){
alert(ck_box);
}
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form name = "frmTest[]" id="fm_submit">
<input type="checkbox" value="true" checked="true" >
<input type="checkbox" value="true" checked="true" >
<input type="checkbox" >
<input type="checkbox" >
<input type="submit" id="fm_submit" name="fm_submit" value="Submit">
</form>
<div class="container"></div>回答by namklabs
$('#frmTest').submit(function(){
if(!$('#frmTest input[type="checkbox"]').is(':checked')){
alert("Please check at least one.");
return false;
}
});
is(':checked') will return true if at least one or more of the checkboxes are checked.
如果至少选中了一个或多个复选框，is(':checked') 将返回 true。
